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Circuit Functions
OVERHEATING CONTROL STATUS
OPERATION
TXV Operation
The measurement of refrigerant flow to the evaporator is the
exclusive function of a TXV. It must measure this flow at precisely
the same rate at which the refrigerant is evaporated by the heat
charge.
The TXV does this by maintaining the coil with enough refrigerant
to maintain the correct superheat of the suction gas leaving the
evaporator coil.
The TXV regulates flow in response to charge superheat.
If it is suspected that a TXV is not operating properly, checking
for overheating is the only way to be sure. Do this with precision
instrumentation to obtain meaningful results.
Operating overheat of 8°F to 12°F are considered normal. Here
are some "tips" to help in detecting and fixing performance
failures in a TXV:
• Check the bulb to make sure it is properly connected to
the suction line. If you can move the bulb manually, it is not
properly secured.
• The bulb must be perfectly insulated to protect it against the
effects of a draft.
• Check the equalizer line for restrictions (kinks) or signs of
frost. A frosted equalizer line indicates internal leakage and
will require valve replacement. Repair or replacement of
a bent equalizer will be necessary for the valve to operate
properly.
TXVs are designed to measure liquid refrigerant flow. If the
refrigerant at the valve inlet contains flash gas, the valve capacity
will be reduced. Make sure that the system is properly charged
and that there is some subcooling at the valve inlet before
discarding the TXV.
www.clima-flex.com
Dimensions (Mm)
Adjustable - ODF connections with 1/4" equalizer
Non-adjustable - Odf connections with 1/4" equalizer
Connections
A
3/8 ODF
41.9
1/2 ODF
41.9
5/8 ODF
54.6
7/8 ODF
54.6
1-1/8 ODF
61.0
67
Dimensions
B
C
D
41.9
9.6 (3/8)
8.6
41.9
12.8 (1/2)
12.2
54.6
16.0 (5/8)
19.0
54.6
22.3 (7/8)
19.0
61.0
28.7 (1-
23.1
1/8)
iom-clic-cf-eng
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